The non-perturbative QCD Debye mass from a Wilson line operator

Abstract According to a proposal by Arnold and Yaffe, the non-perturbative g 2 T -contribution to the Debye mass in the deconfined QCD plasma phase can be determined from a single Wilson line operator in the three-dimensional pure SU(3) gauge theory. We extend a previous SU(2) measurement of this quantity to the physical SU(3) case. We find a numerical coefficient which is more accurate and smaller than that obtained previously with another method, but still very large compared with the naive expectation: the correction is larger than the leading term up to T ∼10 7 T c , corresponding to g 2 ∼0.4. At moderate temperatures T ∼2 T c , a consistent picture emerges where the Debye mass is m D ∼6 T , the lightest gauge invariant screening mass in the system is ∼3 T , and the purely magnetic operators couple dominantly to a scale ∼6 T . Electric (∼ gT ) and magnetic (∼ g 2 T ) scales are therefore strongly overlapping close to the phase transition, and the colour-electric fields play an essential role in the dynamics.